Cum. You've heard the word a million times. You know it's slang for
semen, or the fluid ejaculated from the tip of your penis (urethra)
during orgasm. But what exactly is semen?

If you said sperm, you're partly correct. But only around one
percent of the average ejaculate (or "load") consists of sperm. The
rest is made up of secretions from parts of your genital-urinary
tract.

What's sperm got to do with it?

Biologically speaking, the main purpose of semen is to help sperm
survive their journey to a female's egg, where fertilization occurs.
In this respect, semen acts like a team of bodyguards; it carries
sperm along, nourishes them and helps deliver them safely to their
destination.

Sperm are produced in the testicles. They then spend 60 to 90 days
in the epididymis (the coiled tubes draped above the testes), where
they grow to maturity. Amazingly, the average ejaculate contains
between 40 million to 600 million sperm, depending on the volume of
cum.

What else is semen made of?

Fun Facts About Semen

The average volume of ejaculate is around a
half-teaspoon.

A load of ejaculate contains 40 million to 600 million
sperm.

Ejaculate does not have a significant amount of calories.
You'd have to ingest 400 loads to equal the calorie content of a
"death by chocolate" dessert.

Besides sperm, semen is made of secretions from the seven
lower urinary tract structures. These strangely named structures
include: epididymis, vas deferens, ampullae of the vas, seminal
vesicle, prostate, Cowper's glands and glands of Littre. Semen
itself has high concentrations of potassium, zinc, citric acid,
fructose, phosphorylcholine, spermine, free amino acids,
prostaglandins and enzymes, which nourish and protect the
sperm.

How much semen is produced?

The volume of your ejaculate can vary, depending on how well
hydrated you are and how many times you've ejaculated within a short
period of time. The average ejaculate measures around a
half-teaspoon, though it may reach a little over a teaspoon. During a
single sexual experience, the volume of ejaculate is greatest the
first time you cum, and less for each subsequent load. "Remember the
law of diminishing returns," says Franklin Lowe, M.D., M.P.H.,
F.A.C.S., associate director of Urology at St. Luke's/Roosevelt
Hospital Center in New York, NY.

In general, volume decreases with age as the prostate enlarges.
This does not mean potency necessarily decreases, however. "The
greatest misconception about semen is that the amount of ejaculate
fluid is correlated with virility and potency," says Dr. Lowe. "In
fact, sperm count can be normal even in smaller volumes."

Despite anecdotal reports of herbs that can help increase the
volume of ejaculate, there is no medically proven way to improve your
volume, notes GayHealth.com's medical director, Dr. Stephen
Goldstone.

Does semen have a typical look, smell and
taste?

Semen usually appears as an opalescent white fluid that gets clear
and runny within minutes after ejaculation. Often, semen has an odor
that resembles chlorine. And the different parts of semen have
different tastes. "For example, the component from the seminal
vesicle, which is high in fructose [sugar], will be slightly
sweeter than the rest of the fluid," Dr. Lowe explains. That said,
semen characteristics do vary from person to person, month to month.
Small changes in color, smell or taste are not necessarily cause for
alarm, adds Dr. Goldstone.

Blood in your semen can signal a broken blood vessel, which may
result from the force of your ejaculation. If this is the case, the
blood will usually subside after a couple of days. You should contact
your doctor if your semen continues to look brown or red, because
this may signal an infection of the prostate or seminal vesicle, says
Dr. Lowe. A yellowish or greenish discharge from the urethra is
frequently a sign of gonorrhea, a sexually transmitted disease (STD)
that can be cured with antibiotics.

Also consult your doctor if your ejaculate has a strong, foul
smell. This, too, could be a sign of a prostate infection.

What is 'pre-cum'?

Pre-cum is a normal part of the male sexual experience. It is a
clear secretion from the glands of Littre that seeps from the urethra
when you're in a sexually excited state. As the name suggests,
pre-cum precedes ejaculation.

Things you can catch

HIV, gonorrhea, chlamydia, nongonococcal urethritis (NGU) and
cytomegalovirus (CMV) can all be transmitted through semen. "Safer
sex is imperative to prevent the spread of venereal disease," says
Dr. Lowe. "The exchange of body fluids can exchange all bacteria and
viruses."

Like semen, the biological function of pre-cum is to protect the
sperm. Pre-cum is an alkaline, which neutralizes the acid levels in
urine. By lowering the acid levels, sperm have a better chance of
surviving their trip through your urethra.

The quantity of pre-cum (if any) can widely vary, depending on the
guy and his level of sexual stimulation.

If you're HIV-positive, your semen may contain high levels of HIV,
even if your blood levels show low or undetectable amounts of the
virus.

Can I get HIV or STDs from pre-cum or
semen?

Yes, both pre-cum and semen can transmit HIV and STDs like
gonorrhea, nongonococcal urethritis (NGU) and cytomegalovirus (CMV).
"Safer sex is imperative to prevent the spread of these diseases,"
says Dr. Lowe.

Unprotected oral, anal and vaginal sex all carry risks for HIV and
STD transmission. In the case of HIV, unprotected anal sex is the
highest risk sex act two men can perform. We do know that unprotected
oral sex is much less risky than unprotected anal sex -- particularly
if you don't swallow cum or take a load in your mouth. However, it's
important to remember that low risk is notno risk. Condom use is the
best way to protect yourself from HIV transmission during sex.

If you have HIV, your semen may contain high levels of the virus,
even if you're taking antiretroviral medications and have a low or
undetectable amount of virus in your blood. This means that patients
with no detectable blood viral load can still transmit HIV to their
sexual partners.

In a study published in the New England Journal of Medicinein
1998, HIV-positive men with no detectable levels of HIV in their
blood still had HIV DNA (provirus) present in cells within their
semen. The researchers found that the provirus was able to replicate
HIV when antiretroviral medication dosages fell. In addition, the
provirus can be transmitted to sexual partners, who will then become
infected with HIV.